Bit-brace fastening



(No Model.)

B. E! BOSE.

BIT BRAOE FASTENING.

No. 275,860. Patented Apr. 17,1883.

UNITED STATES PATENT OFFICE.

ELMORE ErRQSE, OF SPRINGFIELD, MASSACHUSETTS.

BlT-BRACE FASTENING.

SPECIFICATION forming part of Letters Patent No. 275,860, dated April17, 1883.

(No model.)

To all whom it may concern:

Be it known that I, ELMORE E. RosE, of Springfield, in the county ofHampdeu and State of Massachusetts, have invented a new and usefulImprovement in Bit-Brace Fastenings, of which the following is aspecification and description.

The object of my invention is to provide a fastening for bit-braces andbreast-drills in which to secure the drill or boring-bit,whereby thedrill or boring-bitwill be securely held during the operation of boringor drilling; and I accomplish this by the mechanism substantially ashereinafter described, and illustrated in the accompanying drawings, inwhich- Figure I is a side view of a breast-drill provided with myimproved fastening. Fig. II is a side view of myimproved fastening asapplied to a bit-stock. Fig. III isa longitudinal section of thefastening at line B of Fig. II. Fig. IV is an end view of the fastening.Fig. V is a perspective view of thejaws, jaw-stem, and the block whichholds and actuates the jaws. Fig. VI is a perspective view of thejaw-stem to which the jaws are secured. Fig. VII is a perspective viewof the threaded block which is inserted into thejaw-stem and engageswith the interior thread of the operating-sleeve, and Fig. VIII is aperspective view of one of the springs which operate to open the jaws ofthe fastening.

In the drawings, 2 represents the shank of a bit-brace or drill-holder,to which the fastening is secured. 1 represents the socket, which ishollow, and through which is made a mortise, 18. This socket 1 ispermanently secured to the shank 2 by being made solid therewith or bybeing brazed thereto, and is provided with asleeve, 3, having aninterior screw-thread made therein nearly or quiteits whole length.Thejaws 11 are each provided with a recess, 10, made on theinside of thejaw atalittle distance from the inner end of each, which recess engageson a laterally-projectinglip, 9, of corresponding form, made on eachside at the end of thejaw-stem S, and two narrow cuts or slots, 13, aremade in thejaw-stem, one on each side of and close to the shank, intoeach of which is secured a flat spring, 12, preferably by upsetting themetal of the jaw-stem against the spring, so that each spring will beheld firmly in its slot in the jaw-stem, with its freeend bearingagainst the outer face of the jaw at the inner end, as shown clearly inFigs. III and V, the inner end of the jaw being preferably beveled forthe bearing of the spring against it, as shown at 15 in Fig. V. Theouter face of each jaw, at 17, is inclined inward near its outer end andfor a short distance from the end with referenee to the remainder of itslength, as shown in Figs. III and V, and this outer face of each jaw isforced outward against the end of the opening 16 in the socket by theinward pressure ofeach spring 12 against its jaw behind the lip 9. Ablock, 6, having a screw-thread made on each end to engage with thescrew-thread on the interior of the sleeve 3, is fitted to and insertedin a mortise, 14, made through the enlarged part of thejawstem, and anannular groove,5,is made around the socket 1, inside the sleeve 3.

To put the parts together the jaws 11 are placed one on each side theshank 8, with the lips 9 in the recesses 10 on the inside of the jaws,and with the free end of each spring 12 hearing on the outer face of thejaw or on the beveled recess 15 at the inner end of thejaw, and thejaw-stem is then inserted into the through said jaw-stem coinciding withthe mortise 18 through the socket. block 6 is then inserted into themortise 14 through the mortise 18 in the socket into its position shownin Fig. III, and the sleeve 3, which, before the block (3 was inserted,was moved back as far as possible upon the shank of the bit-stock, isthen turned forward and screwed onto the block 6, with the forward endof the sleeve against the shoulder 20, and a screw, 4, is then turnedinto a threaded hole made in the sleeve, with the inner end of the screwin the annular groove 5, which holds the sleeve in its placeon thesocket. As the sleeve 3 is turned in one direction the block 6, jawstem,and jaws are moved forward, and as the springs 12 press inward againstthe inner ends of the jaws their outer ends are opened and cause theinclined outer side of each to ride against the end of the opening inthe socket at the end. If the sleeve be turned in the other direction,the block 6 and jaw-stem are moved backward, drawing thejaws in again,and as socket lat the open end, with the mortise let,

The threaded the inclined back sides of the jaws ride against the endsof the opening in the end of the socket the jaws are forced together,firmly gripping the shank of a bit or adrill, it placed between thejaws, so that the bit or drill will be firmly held in the jaws whileboring with the brace.

It is evident that this device may be secured to the shank of anyordinary drill-stock as well as that of a bit-brace without departingfrom the invention in the least.

The opening in the end of the socket is made of the proper width to justreceive the jaws in the direction of their thickness, so that when thejaws are in place in the socket they just fit the opening as to theirthickness, but so as to slide freely therein, with the inclines on thejaws riding against the ends of the opening in said socket.

Having thus described my invention, what I claim as new, is-

1. The combination, in an improved bit-brace fastening, of the mortisedjaw-stem 8, the threaded block 6, the recessed jaws 11,inclined of theshank, and an incline on the outside of 35 each jaw, near its outer end,to ride against the end of the opening in the socket, two springssecured in said jaw-stem, with their free ends pressing inward againstthe inner ends of the jaws, and a block fitted and inserted into theslot or mortise through said jaw-stem, substantially as described.

, ELMORE E. ROSE. \Vitnesses:

T. A. CURTIS, N. E. DWINNELL.

